I had no idea that happened until my father died of Alzheimer's. Sometimes they can get mean.

On a lighter note, I went to see my dad a few weeks before he passed. He was sitting in a chair all by himself. I put my hand on his knee and said, "How you doing Dad?" He looked at me and said, "If you do that again I'm going to knock your block off." (Needless to say I didn't put my hand on his knee again)